This is the fifth article in our series Making Cities Work. It considers the problems of providing critical infrastructure and how we might produce the innovations and reforms needed to meet 21st-century needs and challenges.

In other areas (often in less-developed contexts), infrastructure development lags behind peripheral expansion. Informal settlement patterns, rapid and unequal peri-urbanisation and high degrees of social segregation characterise these areas.

In more mature suburban environments and in high-growth regions, gridlock, system failure and all manner of bottlenecks are typical.

The various forms of infrastructure need to be situated within their societal context. Infrastructures are contested between constituencies and are powerful instruments of social regulation. Central to our argument is the view that the ramifications stretch far beyond the expectations and control of decision-makers.

All infrastructures share a common characteristic. At the very core of the concept is the role of supporting the functioning of different aspects of society.

We differentiate two types of infrastructure.

The first is the “hard” physical, public-works-type infrastructure: roads, highways, water and sewage systems, railways, wires, cables and transmitters. This includes the political, organisational know-how and financial requirements for their design, construction, operation and maintenance.

The second category can be described as “soft” or social infrastructures. These consist mostly of services.

Infrastructures are central to newer, non-central portions of metropolitan regions in this era of global suburbanisation. This is because they operate as conduits, facilitators and sometimes the main ingredient of that extension. Infrastructures order these suburban landscapes and make them accessible.

One feature common across the suburban environment is its fragmentation. Fragmentation is built into the morphology of the suburb. Its territory is dissected by the transport and utility infrastructures connecting the central city to its hinterland and the rest of the world.

An important, underrated aspect of suburban infrastructures is their tremendous importance for how the entire urban region functions. Suburban infrastructure, often thought of as merely functional for the suburban constellation itself, remains multi-scalar – that is, it also supports metropolitan and higher-scale purposes.

Thus, infrastructures work as fragmenting and sorting mechanisms of complex suburban landscapes.

Infrastructures play a central role in building suburbs but are also the foundation for the retrofitting of ageing peripheral areas. Keller Easterling describes the infrastructural grid as:

In this sense the suburbs are a “zone”. And suburbanisation is a horizontal division of labour, a giant production grid, a gargantuan spatial factory floor spread across city and society. And networked infrastructures enable it.

Infrastructure connects and excludes

With fragmentation come inequality and marginalisation – access to and exclusion from suburban infrastructures. The global suburb is a place of extremes. High levels of unevenness in the availability of infrastructures reflect and intensify this.

Infrastructure issues are exacerbated in the suburbs. Several of their characteristics contribute to this situation: their recent nature, rapid development, economic polarisation and sprawling nature.

The infrastructure deficit in suburban areas results from the combined effects of accelerated suburban growth and insufficient funding. The latter reflects difficult economic circumstances and the predominance of other public sector expenditure priorities.

Infrastructure deficiencies are most severe in informal settlements. Governments largely overlook their needs, and the acute poverty of residents prevents reliance on locally funded infrastructure programs. The shortage or absence of water and sanitary infrastructures contributes to low health and longevity indicators.

Confronted with the need to overcome multiple forms of infrastructure difficulties, the suburbs are a likely source of urban infrastructure innovation and fertile spawning grounds for new solutions. We thus expect the future of urban infrastructures to emerge from the suburbs.

The impetus is great for infrastructure innovations to fill the gap between need and availability and overcome the inappropriateness of prevailing systems. In this sense, suburbs can be seen as laboratories for new infrastructure.

This article draws on a research paper by the authors in a new special issue of the international journal, Urban Policy and Research, on critical urban infrastructure. These matters have been taken up in more detail in two forthcoming books by the authors, Global Suburban Infrastructure: Social Restructuring, Governance and Equity (University of Toronto Press) by Pierre Filion and Nina Pulver, and Suburban Planet (Polity Press) by Roger Keil.